1. connect the the red+ wire from the fuse to battery +; connect the black wire from the reply to the battery -;

2. connect the wire for lights bar from the relay; (red/black correspond to the wire of LED light bar)

3. connect the white +/black- wire of the switch to battery or any place of your car system to get power for the switch

4.turn on on/off button of switch to test the LED light bar

Details of auto bmw wiring harness

Advantages:

Will work with all light bars *IF* you cut the special connector off as shown. Some light bars on the market may have this unique plug, some do not.Built with silicon protection cover and heavy gauge wiring.40A Max Load (0-300W Light Bars)

1 x 14VDC 40A Driving Lights Wiring Loom HARNESS KIT SUPPLIED WITH MOUSE STYLE SWITCH New heavy duty wiring suitable for HID and Halogen lights and LED light bars Relay and Fuse included.Easy DIY.Professionally assembled wiring loom suitable for driving lights. Most of the wire ends are terminated with spade/plug or ring fitting for quick fitment. The on/off switch is press button type with adhesive backing for easy mounting. The switching relay is rated to 40A so you could wire 10 or more driving lights (depending on the wattage). Has a built in 40A replaceable fuse holder too. This is a convenience way to wire your driving lights

FAQ

Q1,How to place an order for your products?

A1:Buyers need to send required product details via e-mail. Then a reasonable quotation as request would be provided.

Q2.What payment ways do you accept?

A2: We receive TT . Western Union and Paypal. You can choose one of them.

Q3: Do I need to send the defective products back to you for warranty?

A5: No, you don't need to send it back for warranty.
You just need to send us a few pics of the defective lights.